Author Topic: CB400 Four special (Mr Sinx II )  (Read 406 times)

Offline Northy

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CB400 Four special (Mr Sinx II )
« on: October 09, 2018, 08:02:44 PM »
Right any purist please look way now before you go mad and say why wreck cb400f and make special out of it .

OH also long thread alert …if your bored just look at the pictures ;-) Oh will be lots of typos as well   :D

Why a 400 four ,well back in 70/80 I created this and number of variations and still had standard yellow one VKK 333S.

 I sold the bike in 1993  for £350 plus a mountain of spares (DOH !! ) well the engine had done over 150k, was on its second frame, iffy wiring and even the ARE alloy wheels where a bent in places. Ironically nothing I couldn’t fix now. So some 30 yrs on , my spannering skills are better than that poor cheeky kid on the “flying tampon” as mates  used to call it. Its was called Mr Sinx, after our cat (bloody vicious thing!)

Well at the time of writing I have two other 400f that are rolling restorations. 2 frames and yet another mountain of part worn 400 bits. Also over the last few years done a few restoration to high standard and a couple of specials.(read I’m handy with spanner and a picky sod too)

So this will be a recreation of Mr Snix but I might move away from the clip ons etc , so more like the Mocheck Harrier (to save my back & wrists). So I’ve already have picture of how it will look in my head and I know what I need but finding them and making them fit is the fun bit  (need a set of Alloys)   

So where does ones start with just frame, engine and plie of bits …the carbs of course. I needed a clean set for one of the other bike which was suffering odd running.(turned out to be the coils). The Bike bits had been sitting for excess of 7yrs in  garage (working one with sooty diesel, brake dust and damp etc )  So the carb where stripped right down 

Tip one , don’t disassemble the rod mechanism if don’t have to. The rod that runs across the carbs to link them together runs in two bronze bushes. However there is also a brass pin in one mount that hold the bush in place and locates pin on the rod. To remove the rod you need to drill out this brass pin or the bush with break up if you try to remove the rod. However drilling out the pin a PTA its only 3mm dia and can easy go into the ally mounting. See picture even drilling the pin didn’t help cracked anyway!!
So some clean carbs , a with re-plated metal bits. I used stainless bolts and this not going to standard anyway.

Good job I've spare set of carbs

So next engine, I wasn’t expecting great things from this. The clock said it had done 43,000 miles and it showed signs of previous split cases and nasty bodges. As I was  stripping this down to last bits, I didn’t bother deep cleaning it before hand

Ohh err

The thread on bolt that locks cam chain adjuster had been chewed up badly but managed to heli coil it. Phew

Spot the odd one out

Two head bolt where finger tight and the cam chain was starting chew its way into the adjuster (they all do that sir). Which is why there was no wear on the guides.
Then the good news the clutch looked like new. I even found my old home made clutch holding tool in the not use often “tool box” last used  25 yrs ago

The primary chain, is very sloppy and need a new one of those. The bore was OK , with marking where the piston had been and still on standard piston bit all looking a bit tied with one broken ring. I measured them all up and there just outside the recommended tolerances, could put new std piston and new rings  and it would run but it deserves a rebore.

So do I go for the oversized 54mmbore kit or just take it 0.25mm OS. The cost using kits from Cruzinimage_uk is the same. I tempted by the big bore (sounds good and gains brownie point when talking bollocks at the cafe)  but then reality kicks in and its only  on a 400  if I need to go faster there’s an modern 750 in garage.   However welcome your thought on this ??.

There was much sludge in sump and bottom of the cases but hardly any metal bits …all good.

Main bearings all Ok but the big end showing wear so they will be replaced ….bloody expensive at £10.74  per half shell ….

All the valves have been removed and the head looks in fine shape no damaged fins, rocker spindles with bit of wear and valve seats good.Cams  all good , wear but nothing  bad.
So no sheared screws or bolts, expect general wear no nasty surprises and only two threads required a helicol. I do them when I see on strip down as the stuff is going to be cleaned after so any bits of ally get washed away.  Not bad at all it would have run no doubt but no very well.

Tip 2  Rotor removal is required for replace the end seal and best  done once the crank removed,. you can’t do without splitting the cases due to the lip on the seal. You could take a hammer to it, dig out the special tool (if you have one ) with a 18x1.5 thread it to “pull” the rotor  off. However the thread a size is the same of many car sump plug or Lamaba sensor plugs available for £2.  Sorted !!   

Next ……the case of clean the cases!!
Got quoted £140  to vapour blast the  cases,head. barrels etc  .......Sod that, out with chemicals.
« Last Edit: October 15, 2018, 09:08:53 PM by Northy »
How many is too many bikes ..... when you have no space left.

Offline SumpMagnet

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Re: CB400 Four special (Mr Sinx II )
« Reply #1 on: October 09, 2018, 08:19:21 PM »
Personally..I have no issue with someone restoring an old bike in a less than standard way. The way I see it, you have put another old bike back on the road, rather than let it rust away in a shed somewhere. Or worse...restored it and then stuck it on a turntable never to run again...just to be looked at.

Back in the day, I hardly ever had a 'stock' bike and instead had aftermarket seats, bars, fairings, shocks, fork braces and all the other tat the fashion trends said you had to have.

On top of are making something personal to you....Hope it ends up as good as you remember!

CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Trigger

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Re: CB400 Four special (Mr Sinx II )
« Reply #2 on: October 09, 2018, 08:55:12 PM »
Nowt wrong with those crank case shells from the picture, measure them up  ;) Much cheaper than new ones  ;D

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #3 on: October 09, 2018, 10:36:03 PM »
its big end that have gone ...I'll  get some piccy's of those.
How many is too many bikes ..... when you have no space left.

Offline Bryanj

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Re: CB400 Four special (Mr Sinx II )
« Reply #4 on: October 10, 2018, 01:17:05 AM »
If the cranks worn its toast cos you cant regrind them or rather if you do there are no shells made

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #5 on: October 14, 2018, 05:12:06 PM »
Crank is good , see piccy


Big ends look like this , worn but nothing nasty

Just new shells needed.All david silver was offering  at stafford was £1 delivery for order placed at the show and I've long list of stuff I need could remember it all.

Set of cases nearly ready for painting , mainly used paint striper , small wire bush  attachment , then wash in thinner , will need another clean [/URL][/img]

Been working on the manky side covers ...getting there slowly

« Last Edit: October 15, 2018, 09:11:17 PM by Northy »
How many is too many bikes ..... when you have no space left.

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #6 on: November 12, 2018, 05:35:38 PM »
Ok having be side tracked with decorating time , its time to move on with Mr Snix

Ok cases clean up,

Sprayed , gloss black , used Hycote engine enamel  not too bad and re-plated my engine bolts  but  they just would shine up very well , suspect too cold a solution, the angle held in electrolyte and they were rough to start with.

Having sussed out then I had Yellow big end shells (oh or misses) I was going to go like for like as they weren’t that worn but suspect that I could go up to green set. I re-measured and seemed to playing for ever with plastigauge, clever but all  doing up  undo , do up undo  etc etc is PITA  and  all  to confirm my initial thought and go for green. So a large order was placed with Mr Silver. Luckily in the stash of shares was a new cam chain, two guides but no primary chain.

The head showing signs of the broken ring on No 2  pot  but nothing scary
Note the heads not be been cleaned properly at this piont,and will take a skim off the head. 

Here’s  a thing valve collets, they must the experts in sod’s law , get one and the other falls out. Normally I  work of Guzzi heads and there massive compared to the 400.   

Here my tool for grinding in valves, then car rubber sucker ones just too big  for tiny 400 valves   

Whilst waiting for engine paint go off and waiting on spares, I turned my attention to the frame. I’ve choice of F1 or F2  frame, so which  one  to use. The biggest factor was the F2 had  a log book , still to apply to F1  frame. 
The ultimate in  a 400 special is a 4 into 4  system and thus the F1  frame might be better one to  do that with, however having had  4 into  4 fitted in past it was PITA  and reduced my ground clearance  to zero.
The lay out the sump/ frame etc  makes it hard to do, So its 4 into 1  it is for this baby.

So F2 frame is stripped and then I started on rear sets, using the old pair of tarozzio rear sets and mount plates in my spares stash. It’s all rough and ready at this point just  to ensure everything works. So its looks a bit rusty and manky at present.

Next for frame is a  “new “  set of forks of  CB400N   ie double disc and box section swing arm,(Note that brand new dresda box section one sold for over £200 on evil bay ) and may need some wheels .

It’s going have ally wheels and not comstars and as Maitland racing no long stock ARE (ally racing eqpt) wheels that were made in Cardiff in early 80’s .  I did ask !!! it was what Mr Snix had originally fitted.   So it will have a double discs and maybe even a rear one.

As  for wheels I have set of GPZ400 lying around and the front wheel popped onto the CB400N forks easy, same spindle size and just need to mill down the space a bit each side . However the Discs might not line up with the any calipers. So which muppet sold the GPZ400 ones on ebay a year ago. I suspect I might go for a set of modern calipers.

The rear wheel is different matter ,the GPZ400 wheel has a massive rear disc and the hub is plain too fat and would need to remove 7 mm from the sprocket carrier ,not in impossible but would remove to much ally on the carrier . Added to this just doesn’t fit well with the overall look of the bike , the massive disc  and hub

So I’ll be paying a visit to local bike breakers , with a tape measure, looking for  set of wheels, swing arm, brakes  etc. That will be messy as Larry’s place is not known for clean washed parts (they go in dirty and get dirtier) and much hunting.i.e Honda wheels – “ in that pile over there”

Then the fun starts and it should easier to play the  frame without an the engine in it (noting sprocket alignment)   

OH BTW  Rock horse poo item . clutch adjuster

How many is too many bikes ..... when you have no space left.

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #7 on: January 26, 2019, 08:13:09 PM »
So what have I’ve been  doing ?…..well this arrived just before Christmas  and I just had to play with it , its runs and is on the road.(stood for 25yrs)

(appear date on camera is 10yrs out)

Then Christmas and a stinky cold arrived.

So back to Cb400F  special

I had by now given up any hope of set of alloys for bike and was starting on std hub , double discs laced to flanged ally rims ..mock up with manky wheels.   

Then a set of ARE wheels, which needed work, appeared on ebay …and didn’t win them went for silly money y, but in a jammy git moment a set of CMA wheels appeared on Ebay  for about 1 hr  and were snapped up. In good condition one bearing need replacing and the black paint black came off to relieve 2  shades of gold , one red and finally grey, assume primer. So they are ready for painting but too cold for that.  Piccy shows a lovely home made washer that sits behind the large circlip …..

OK sort  out the forks , discs and calipers …….let nightmare start.

First off the caliper pistons from a second hand set off ebay (CB400N ones) had seized, one popped out with lots of heat and compressed air. The other one despite being soaked required more radical action . Weld a bolt to piston and using a set of spacers pulled it out. One new piston required.

Forks were a set of Cb400N one that I had and knew there was some play on them and I thought new bushes …however these  earlier one don’t have bushes both leg and slider  were worn …  ebay again for set of forks. Found set but the description was iffy, even though I phone the guy to check there was no play, these were later type with bushes but one was missing ..sloppy fit or what.   

Discs  CB 400N have 5 holes CB400f have 4 holes ……drill hub ? or  drill disc chose the later

Speedo drive :-  Nearly gave up on this and was moving to using digital speedo and as used  on lavukitangomonty (bit of orange for you)

The problem being the standard 400F speedo drive output is straight while cb400N is angled to get past the disc but is 5 mm too fat to allow the wheel to be central. Simple remove 5 mm from drive unit , reshape the worm drive to match , make up tab to drive the speedo ….simple took most of a morning and still a tight fit.

Right back to the fame , need to go to powder coater…but what colour ? . I would have liked a dark candy red  this was expensive and would be hard to get  a consistent finish  and I had  things like brake disc/calipers  etc which  I wanted in the same colour. So boring flat red but what shade .

Right time warp back  to  1980  Mr Snix  frame is paint in Massy Ferguson red , later 1983 following an incident with some gravel and a car. The new frame was painted Ford velvet red (burgundy) However the old girl was later used every day transport and the frame once again reverted to bright red. …so which colour, your’ll have to wait on that :-)   

Old bike back in 1993 just before behind  sold , have guess how much ? .....bloody muppet I am.

    So  frame is how with the coaters and just for good measure  I stripped out my red 400/4  so the frame could done as well , its cold and not much is being done. There are two set of 400/4 in boxes and plan is work on the red 400/4 .So there will be another gap in installments.
« Last Edit: January 26, 2019, 10:30:55 PM by Northy »
How many is too many bikes ..... when you have no space left.